I have come back to Metro 2033 for a ranger easy play-through and have reached Polis with zero filters for my gas mask, and to my surprise they are not available at polis. Obviously I could go back to the last place where they are sold, but that is prohibitively far.
Does anyone have any game-play ideas for continuing with zero filters? Otherwise does anyone know any good ways to mod the gamesave to produce more filters? I have the tool "360revolution" that offers the ability to mod saves to "god mode" and "infinite ammo", but even if these work it sounds to me like cracking a nut with a sledgehammer.